Methods for capturing kinetic energy in moving fluids, both compressible such as wind and incompressible such as water, have existed for thousands of years ranging from Heron of Alexandria's wind power machines and water wheels and the Archimedes screw in ancient Greece to modern wind turbines and hydro power generators in use today. Similarly, machines that increase the kinetic energy of, i.e. move, fluids such as fans and propellers by conversion of another form of energy into rotational energy have also existed for thousands of years. Both types of devices typically share blades and a rotating body to which the blades are attached as common design elements.
The deployment and operation of modern wind turbines are plagued by a number of issues such as, for example, vibration, noise, unsightliness, large ground footprints to accommodate high towers for mounting turbines, and potential impact on local environments for larger installations. Some of these issues are caused by the length of the blades required for conventional turbines which directly affects vibration and noise as well as limit the wind speed range in which a turbine may safely operate and produce power.
At the same time, many hydropower installations require diversion of the water supply to feed the turbine in specialized pipes and other structures. The effectiveness of these turbines is also limited by blade design and their configuration on the rotating portion of the turbine. The effectiveness of propellers for propulsion, fans and other devices that convert mechanical energy into fluid movement are similarly affected by blade design and their mounting on the rotating body.
Therefore, a solution which improves the transfer or conversion of energy between fluid motion and mechanical rotation and possibly other forms of energy such as electricity is desirable.